Brain’s Hidden Role In Battling Cancer And Infection

Groundbreaking research reveals how motivation and positive anticipation may help the brain direct the body’s immune response against disease.

Scientists have uncovered compelling evidence that the brain can actively influence the body’s immune system, opening new possibilities for treating infections, cancer and cardiovascular disease through targeted stimulation of specific neural pathways. The findings, led by Professor Asia Rolls of Tel Aviv University, demonstrate that activating the brain’s reward system alters immune activity in different organs, strengthening the body’s ability to respond to various health threats. While much of the research has been conducted in mice, early human studies have also revealed a promising link between brain activity and immune responses following vaccination.

The research provides fresh scientific insight into the long-observed relationship between mental and physical health. Scientists have long recognized that stress, expectation and motivation can influence well-being, yet the biological processes connecting the brain to the immune system have remained largely unclear. According to the researchers, the latest findings suggest that the brain does far more than merely receive signals about illness. Instead, it appears capable of directing immune responses by activating distinct neural circuits depending on the type of disease or injury confronting the body.

Earlier investigations by the same research team showed that the brain can retain a neural “memory” of inflammation. Scientists identified neurons within the insular cortex that became active during intestinal inflammation. When those neurons were reactivated after recovery, inflammation reappeared in the same organ despite the absence of a new disease trigger. Conversely, suppressing those neurons reduced inflammatory activity, indicating that the brain stores and can recreate immune-related responses. Building on that discovery, the current research examined whether neural activity associated with motivation, anticipation and reward could influence how effectively the immune system combats disease.

Central to the study is the brain’s reward system, a network of neurons responsible for motivation, learning and the anticipation of positive outcomes. A key component of this network is dopamine-producing neurons located in the ventral tegmental area (VTA), which communicate with several regions of the brain to regulate behaviour and decision-making. “Our working premise is that when there is a goal and motivation, we mobilize the body’s resources to achieve the goal, including our immune system,” Professor Rolls explained. “Our goal is to understand how that reward system creates different immune responses depending on the challenge we are facing.”

Using advanced chemogenetic techniques, researchers selectively activated specific dopamine-producing neurons in mice, allowing them to examine direct cause-and-effect relationships between brain activity and immune function. The experiments revealed that stimulating the reward system altered immune responses differently depending on the disease. In cancer models, activation changed signals travelling through the sympathetic nervous system to the bone marrow, reducing the suppressive activity of immune cells that normally weaken the body’s ability to attack tumours. As a result, anti-tumour immune responses became stronger. Separate experiments however showed that activating the reward system after heart attacks influenced immune activity in the liver, promoted blood vessel formation and improved repair of damaged heart tissue. Other studies found distinct immune changes involving the spleen, highlighting the brain’s remarkable ability to direct immune responses to different organs based on the specific health challenge.

Researchers cautioned that, these findings should not be interpreted as evidence that positive thinking alone can cure serious illnesses. The chemogenetic methods used in laboratory animals involve highly controlled activation of neurons that does not naturally occur in humans. “Once the effect on the immune system was focused on the liver, once on the bone marrow and once on the spleen, the brain has the ability to know what is happening to the body and activate different targets.” Professor Rolls noted

To explore whether similar mechanisms exist in humans, the researchers conducted a study involving 85 healthy volunteers. Participants underwent functional magnetic resonance imaging (fMRI)-based biofeedback training, learning to increase activity within the brain’s reward circuitry before receiving hepatitis B vaccinations. The study found that individuals who successfully increased activity in the VTA region generally developed stronger antibody responses following vaccination. Those who maintained higher activity levels also tended to rely on cognitive strategies centred on positive expectations. However, researchers did not observe significant differences in overall antibody levels between the study groups, meaning the findings indicate an association rather than proof that brain training consistently enhances immunity.

Scientists stressed that the research should not encourage patients to replace medical treatment with optimism or mental exercises. Conditions such as cancer, infectious diseases and heart attacks remain complex biological disorders requiring evidence-based medical care. Factors including genetics, age, medication, nutrition, sleep and physical activity all continue to play critical roles in determining immune function. Instead, the significance of the research lies in identifying biological pathways through which the brain communicates with immune cells and organs. A deeper understanding of these mechanisms could eventually support the development of complementary therapies using technologies such as magnetic brain stimulation, biofeedback or other non-invasive methods to enhance immune responses alongside conventional treatment.

Professor Rolls said her team’s focus remains on understanding the fundamental relationship between mental states and physical health. “I focus on basic research, trying to understand the essence of the connection between the mind and the physical, how different mental states affect our ability to cope with illness,” she said. “When we understand the networks involved in activating the immune system specifically in certain organs, we will be able to manipulate them to improve the immune response in a targeted manner. There are many tools today that can influence the activity of the nervous system from the outside, for example with magnetic stimulation of the brain. Perhaps in this way it will be possible to improve the fight against diseases.”

Source: The Voice of Science
Author: Joyce Owusu